1. Field of the Invention
The present invention relates generally to power distribution equipment and, more particularly, to a test button assembly for a circuit breaker.
2. Description of the Related Art
Circuit breakers and other power distribution equipment are well known in the relevant art. Circuit breakers are typically configured to interrupt current upon the occurrence of one or more predetermined conditions. For instance, circuit breakers may trip in the event of an overcurrent condition or an under-voltage condition, and they additionally trip in the event of a ground fault or an arc-fault condition if configured to do so. Protection from ground faults and arc faults typically is provided by circuitry within the circuit breaker that is operatively connected with a trip unit of the circuit breaker.
In order to ensure the continued proper and safe operation of such circuit breakers, the ground fault and arc fault detection circuitry is desirably tested on occasion. The testing of such ground fault and arc fault circuitry typically involves the closing of a pair of contacts within a testing circuit that simulates the fault condition. Upon closing of the contacts and simulation of the fault condition, a successful test of the fault detection circuitry will result in the trip unit of the circuit breaker performing a trip operation. The circuit breaker can then be reset. While such testing circuitry has been generally effective for its intended purpose, such testing circuitry has not, however, been without limitation.
Circuit breakers generally are designed in such a fashion to minimize the space occupied thereby. As such, the contacts that are closed in order to test ground fault and arc fault circuitry typically have been mounted directly onto a main printed circuit board of the circuit breaker. In some instances the contacts have been configured as leaf springs that protrude from the main printed circuit board and are deflected into contact with one another in order to close the ground fault or arc fault protection circuit.
The deflection of such leaf spring contacts undesirably results in forces and torques being applied to the main printed circuit board. Since numerous other circuitry components of the circuit breaker are mounted on the main printed circuit board, such forces and torques can result in breakage or other failure of the main printed circuit board and thus the circuit breaker.
Additionally, since such contacts are disposed internally within the circuit breaker, some type of linkage or other motion transfer mechanism must be provided which operatively extends between the contacts and the exterior of the circuit breaker to permit the contacts to be closed from the exterior of the circuit breaker. Such linkages and the like occupy additional space within the circuit breaker and are often less than fully reliable in closing the contacts of the protection circuitry. Such contacts and linkages additionally have been relatively expensive to incorporate into a circuit breaker.
It is thus desired to provide an improved test button assembly for a circuit breaker that overcomes these and other shortcomings of previously known test button designs.
Accordingly, an improved test button assembly for use in a circuit breaker includes a frame and a button member, with the button member being pivotably mounted on the frame. A pair of microswitches are mounted on a printed circuit board that is disposed on the frame. The button member is alternately engageable with the two microswitches, with one of the microswitches being connectable with a ground fault protection circuit, and the other microswitch being connectable with an arc fault protection circuit. In an alternate embodiment, a common electrical contact is mounted on the button member, and a pair of contacts are mounted on the frame, with the common contact being alternately engageable with each of the contacts mounted on the frame. The contacts mounted on the frame are connected with the ground fault and arc fault protection circuits.
Accordingly, an aspect of the present invention is to provide an improved test button assembly that is relatively less expensive to manufacture and incorporate into a circuit breaker than previously known test button systems.
Another aspect of the present invention is to provide an improved test button assembly that is relatively more reliable in function than previously known test button systems.
Another aspect of the present invention is to provide an improved test button assembly that is modular in nature.
Another aspect of the present invention is to provide an improved test button assembly that is configured such that the operation thereof imparts generally no forces or torques to a main circuit board of the circuit breaker.
Another aspect of the present invention is to provide an improved test button assembly for a circuit breaker that occupies minimal space within the circuit breaker.
Another aspect of the present invention is to provide an improved circuit breaker that employs an improved test button assembly.
Accordingly, an aspect of the present invention is to provide a test button assembly for a circuit breaker, the circuit breaker including a first protection system and a second protection system, the circuit breaker including a case formed with a receptacle, in which the general nature of the test button assembly can be stated as including a frame, a button member, the button member being mounted on the frame, the button member being movable with respect to the frame, a first contact, the first contact being disposed on the frame, the first contact being structured to be electrically conductively connected with the first protection system, a second contact, the second contact being disposed on the frame, the second contact being structured to be electrically conductively connected with the second protection system, a common contact, the common contact being operatively connected with the button member, the common contact being movable by the button member to be electrically conductively connectable with the first contact, the common contact being movable by the button member to be electrically conductively connectable with the second contact, and the test button assembly being a discrete unit that is structured to be received in the receptacle and mounted to the case of the circuit breaker as a single assembly.
Another aspect of the present invention is to provide a test button assembly for a circuit breaker, the circuit breaker including a first protection system and a second protection system, the circuit breaker including a case formed with a receptacle, in which the general nature of the test button assembly can be stated as including a frame, a first microswitch, the first microswitch being disposed on the frame, the first microswitch being structured to be electrically conductively connected with the first protection system, a second microswitch, the second microswitch being disposed on the frame, the second microswitch being structured to be electrically conductively connected with the second protection system, a button member, the button member being mounted on the frame, the button member being movable with respect to the frame, the button member being operatively engageable with the first microswitch, the button member being operatively engageable with the second microswitch, and the test button assembly being a discrete unit that is structured to be received in the receptacle and mounted to the case of the circuit breaker as a single assembly.
Another aspect of the present invention is to provide a circuit breaker the general nature of which can be stated as including a case, a trip unit, the trip unit being disposed within the case, a line conductor, a load conductor, the line and load conductors being electrically conductively connectable with one another, the trip unit being operative to electrically conductively connect and disconnect the line and load conductors, a first protection system, the first protection system being operatively connected with the trip unit, a second protection system, the second protection system being operatively connected with the trip unit, a test button assembly, the test button assembly including a first microswitch, the test button assembly including a second microswitch, the test button assembly including a support, the first microswitch being mounted on the support, the second microswitch being mounted on the support, the support being disposed on the case, the first microswitch being operatively connected with the first protection system, and the second microswitch being operatively connected with the second protection system.